進(jìn)度條是當(dāng)我們處理冗長的任務(wù)時(shí)使用的控件，它是以動(dòng)畫的形式讓用戶知道該任務(wù)正在取得進(jìn)展。
在PyQt5中的進(jìn)度條對(duì)應(yīng)組件是QProgressBar，該對(duì)象繼承自QWidget組件。一般在生產(chǎn)業(yè)務(wù)的實(shí)現(xiàn)過程中還需要借助定時(shí)器來實(shí)現(xiàn)的。
在實(shí)際使用的過程當(dāng)中進(jìn)度條的進(jìn)度控制往往還要根據(jù)子線程的業(yè)務(wù)執(zhí)行過程來設(shè)置進(jìn)度顯示。
PyQt5在之前的文章中已經(jīng)多次使用，想必大家都比較熟悉了。若是沒有安裝的話使用pip的方式安裝一下即可。
pip install PyQt5
接下來將本文中使用到的相關(guān)模塊都導(dǎo)入到代碼塊中。
# It imports all the classes, methods, and attributes of the `PyQt5.QtWidgets` module.
from PyQt5.QtWidgets import *
# It imports all the classes, methods, and attributes of the `PyQt5.QtCore` module.
from PyQt5.QtCore import *
# It imports all the classes, methods, and attributes of the `PyQt5.QtGui` module.
from PyQt5.QtGui import *
# It imports the `sys` module.
import sys
# It imports the `time` module and it renames it to `t`.
import time as t
接下來我們創(chuàng)建一個(gè)ProgressBarUI的python類，將所有的進(jìn)度條的布局以及槽函數(shù)放到該類中。
# This class is a widget that displays a progress bar.
class ProgressBarUI(QWidget):
def __init__(self):
super(ProgressBarUI, self).__init__()
self.init_ui()
def init_ui(self):
"""
This function initializes the UI.
"""
self.setWindowTitle('PyQt5進(jìn)度條案例 公眾號(hào)：Python 集中營')
self.setWindowIcon(QIcon('prop.png'))
self.resize(500, 200)
self.progressBar = QProgressBar()
self.progressBar.setValue(0)
self.progressBar.setAlignment(Qt.AlignCenter)
hbox = QHBoxLayout()
hbox.addWidget(self.progressBar)
self.timer = QTimer()
self.timer.timeout.connect(self.listen_step)
self.timer.start(100)
self.step = 0
self.thread_ = WorkThread()
self.thread_.thread_step.connect(self.step_add)
self.thread_.start()
self.setLayout(hbox)
def step_add(self, n):
"""
It adds n to the current value of the counter
:param n: the number of steps to take
"""
self.step = self.step + n
def listen_step(self):
"""
> The function `listen_step` is called by the `listen` function, and it returns the next step in the conversation
"""
if self.progressBar.value() >= 100:
self.timer.stop()
else:
self.progressBar.setValue(self.step)
創(chuàng)建一個(gè)子線程WorkThread繼承自QThread用于處理所有的業(yè)務(wù)實(shí)現(xiàn)邏輯。
# This class is a subclass of QThread and it's used to create a thread that will run the function that will be passed to
# it
class WorkThread(QThread):
# A signal that is emitted when the value of the counter changes.
thread_step = pyqtSignal(int)
def __init__(self):
"""
A constructor. It is called when an object is created from a class and it allows the class to initialize the
attributes of a class.
"""
super(WorkThread, self).__init__()
self.working = True
def __del__(self):
"""
A destructor. It is called when the object is destroyed.
"""
self.working = False
def run(self):
for n in range(1, 101):
self.thread_step.emit(1)
t.sleep(0.1)
使用python模塊的main函數(shù)，將整個(gè)應(yīng)用加入到系統(tǒng)的主體循環(huán)中。
# A common idiom to use this as the last statement in a module (a file that contains Python code).
if __name__ == '__main__':
app = QApplication(sys.argv)
main = ProgressBarUI()
main.show()
sys.exit(app.exec_())
